CVE-2026-87121

Out-of-bounds write in lwIP TCP/IP Stack MQTT Client Application

CVSS 3.1 9.8 CRITICALCVSS 4.0 9.3 CRITICALCheck source for fixed versionsKEV status unknown

Original advisory

cve-program · CVE-2026-87121

Published

lwIP TCP/IP Stack MQTT is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device.

Read the publisher's advisory

Affected versions, risk and source history

Exploitation and risk

Source status

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cve-program · CVE-2026-87121

Published

Out-of-bounds write in lwIP TCP/IP Stack MQTT Client Application

lwIP TCP/IP Stack MQTT is vulnerable to an out-of-bounds write, which may allow an attacker to gain full code execution on the device.

Source published: 22 Sep 2026 19:48:25 UTC
Source modified: 22 Sep 2026 20:23:09 UTC
Saved here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS 4.0 · 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N